A sentence is a group of words that expresses one complete idea ( thought or feeling ). Sentences generally begins with a capital letter and end with a period, question mark, or exclamation point. All sentences must have a subject and a verb. Following its subject and its verb, a lot of sentences have also an object and a complement.
Based on the purpose of the speaker or writer, sentences can be differentiated into four group or class. You can see the four kinds of a sentence as follows.
1. The declarative sentence is used to make a statement of fact, wish, intent, thought or feeling. Example : She has informed me her email address.
2. The imperative sentence is used to express a command, request, or direction. The subject "You" is implied. Example : (You) Call me every day.
3. The interrogative sentence is used to ask a question. Example : Do you know his name?
4. The exclamatory sentence is used to express strong feeling. Example : Look out! What a nice day!
Based on its structure, sentences can be classified into three groups. Let’s see those three groups of sentences below.
1. Simple sentences. Simples sentences always consists of a subject and a verb and/or object and/or complement. Example : Kentaro speaks English well.
2. Compound Sentences. Compound sentences always consists of two or more independent clauses. These two clauses are connected by coordinating conjunctions (for, and, so, but, or, yet) Example : I like her and she likes me, too.
3. Complex sentences. Complex sentences always consists of two or more clauses. One of the clause is independent clause and the other is dependent clause. Example : Before I met her, I had talked to her parent nicely.
Sentences can consist of two or more elements. See the following table.